Lymphocytes from the site of disease but not blood lymphocytes indicate the cause of arthritis.

The [3H]thymidine uptake procedure for measuring lymphocyte responses was applied to lymphocytes derived concurrently from synovial effusions and from peripheral blood. The stimulating antigens were crude preparations of those micro-organisms that are related to the enteritis and the non-gonococcal urethritis that precipitate reactive arthritis. Salmonella, shigella, and campylobacter antigens stimulated synovial but not peripheral blood lymphocytes in eight cases of enteric reactive arthritis. Ureaplasma or chlamydia antigens, or both, stimulated synovial lymphocytes in all 12 cases of sexually transmitted reactive arthritis, whereas peripheral blood lymphocytes were only stimulated in four of the 12 cases. In 14 cases of rheumatoid arthritis reactions to either enteric or ureaplasma/chlamydia antigens were minimal from either synovial or peripheral blood lymphocytes. It is concluded that synovial rather than peripheral blood lymphocytes indicate the microbiological cause of reactive arthritis and that similar studies of lymphocytes from the site of local disease might be productive in other diseases.